Method and system for forming a silicon oxycarbide layer and structure formed using same

ABSTRACT

Methods of forming a silicon oxycarbide layer on a surface of a substrate are disclosed. Exemplary methods include providing an oxygen-free reactant to a reaction chamber and performing one or more deposition cycles, wherein each deposition cycle includes providing a silicon precursor to the reaction chamber for a silicon precursor pulse period and providing pulsed plasma power for a plasma power period to form the silicon oxycarbide layer.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims priority to U.S. Provisional Pat. ApplicationSerial No. 63/297,332 filed Jan. 7, 2022 titled METHOD AND SYSTEM FORFORMING A SILICON OXYCARBIDE LAYER AND STRUCTURE FORMED USING SAME, thedisclosure of which is hereby incorporated by reference in its entirety.

FIELD OF INVENTION

The present disclosure generally relates to methods and systems forforming structures suitable for forming electronic devices. Moreparticularly, examples of the disclosure relate to methods and systemsfor forming layers comprising silicon oxycarbide.

BACKGROUND OF THE DISCLOSURE

During the manufacture of electronic devices, fine patterns of featurescan be formed on a surface of a substrate by patterning the surface ofthe substrate and removing material from the substrate surface using,for example, wet etch and/or dry etch processes. Photoresist is oftenused as a template for such patterning of the surface of the substrate.

A photoresist pattern can be formed by coating a layer of photoresistonto a surface of the substrate, masking the surface of the photoresist,exposing the unmasked portions of the photoresist to radiation, such asultraviolet light or an electron beam, and removing a portion (e.g., theunmasked or masked portion) of the photoresist, while leaving a portion(e.g., the other of the unmasked or masked portion) of the photoresiston the substrate surface. Once the photoresist is patterned, thepatterned photoresist can be used as a template for etching material onthe substrate surface in regions in which the photoresist was removed toform a transferred pattern in a layer underlying the photoresist. Afteretching, remaining photoresist can be removed.

As a size of devices decreases, traditional photoresist techniques maynot be suitable to form patterns of desired size. In such cases,multiple patterning techniques can be used to allow for patterning andetching of features that can be smaller than the exposure resolution ofthe photolithography process. A multiple patterning process can includeforming a spacer about patterned features (e.g., patterned photoresist),removing the patterned features to form patterned structures, and usingthe patterned structures as a mask during a subsequent etch.

Although such techniques may work relatively well in some applications,some multiple-patterning processes can result in undesired plasma damageto an underlayer. This phenomenon generally becomes increasinglyproblematic as the size of the patterned structures decreases.

Techniques to address the underlayer damage include using lower RF powerduring deposition of a spacer layer. However, such techniques can resultin low plasma reactivity and/or plasma ignition failures. Other attemptsto address unwanted damage to the underlayer have resulted in spacerfilms with degraded film properties (e.g., lower etch selectivity and/orrelatively high spacer material etch rates).

Accordingly, improved methods of forming patterned structures on asurface of a substrate and of achieving desired spacer materialproperties are desired. Further, device structures, which include suchpatterned structures, are also desired. And, systems for performing themethod are also desired.

Any discussion of problems and solutions set forth in this section hasbeen included in this disclosure solely for the purpose of providing acontext for the present disclosure, and should not be taken as anadmission that any or all of the discussion was known at the time theinvention was made.

SUMMARY OF THE DISCLOSURE

Various embodiments of the present disclosure relate to methods offorming a silicon oxycarbide layer. The silicon oxycarbide layer can beused in the formation of devices, such as semiconductor devices andother electronic devices. More particularly, as described in more detailbelow, the silicon oxycarbide layer may be well suited for use in theformation of spacers during the formation of an electronic device.

While the ways in which various embodiments of the present disclosureaddress drawbacks of prior methods and systems are discussed in moredetail below, in general, various embodiments of the disclosure provideimproved methods of forming a silicon oxycarbide layer with desiredproperties, such as a relatively low etch rate and a relatively lowdielectric constant. As set forth in more detail below, examples of thedisclosure include use of an oxygen-free reactant and a pulsed plasmapower. Use of the oxygen-free reactant can mitigate undesired oxidationof underlying layers during the formation of the silicon oxycarbidelayer. Use of the pulsed plasma can facilitate formation of the siliconoxycarbide layer with desired properties and also mitigate damage to anunderlying layer or substrate.

In accordance with examples of the disclosure, a method of forming asilicon oxycarbide layer is disclosed. The method can be used forforming electronic devices, using, for example, multiple patterning(e.g., spacer-defined double patterning) techniques. An exemplary methodincludes providing a substrate within a reaction chamber of a reactor,providing an oxygen-free reactant to the reaction chamber, and formingthe silicon oxycarbide layer by performing one or more depositioncycles, wherein each deposition cycle comprises: providing a siliconprecursor to the reaction chamber for a silicon precursor pulse period,the silicon precursor comprising at least one oxygen atom per moleculeand providing pulsed plasma power to an electrode for a plasma powerperiod to form a plasma within the reactor. The oxygen-free reactant caninclude, for example, one or more of argon (Ar), hydrogen (H₂). Thereactant can be continuously provided to the reaction chamber during oneor more deposition cycles. In accordance with examples of thedisclosure, the plasma power period is between 0.01 and 5.0 seconds. Inaccordance with further examples, a plasma pulse period is between about0.01 and 0.2 msec. In accordance with additional examples, a plasmapower on-time duty cycle is greater than 0 and less than 75% or betweenabout 10 and about 50%. In accordance with yet further examples, themolecule comprises one or more Si—O bonds. Additionally oralternatively, the molecule can include one or more Si—C bonds. Inaccordance with further examples, a chemical formula of the siliconprecursor can be represented by (R^(i))_(4-x) Si(O—R^(i))_(x), where xcan be between 1 and 3, (R^(i)—O—R^(ii))_(4-x) Si(O—R^(i))_(x), where xcan be between 1 and 3 and (R^(i) _(3-x) Si(O—R^(i))_(x))—R^(ii)-(R^(i)₃₋ _(x) Si(O—R^(i))_(x)), where x can be between 1 and 3. Wherein R′ isan independently selected alkyl group (e.g., a C1-C3 alkyl group) andR^(ii) is an independently selected hydrocarbon (e.g., a C1-C4hydrocarbon). As noted above, in some cases, the silicon oxycarbidelayer is used to form a spacer. Additionally or alternatively, adielectric constant of the silicon oxycarbide layer is less than 4.5 orless than 4—e.g., between about 3.5 and about 4.25. Additionally oralternatively, a wet etch rate of the silicon oxycarbide layer in 0.5%dilute hydrofluoric acid is less than 1 nm/minute.

In accordance with further embodiments of the disclosure, a structure isprovided. The structure can include a layer formed according to a methodas set forth herein. In accordance with examples of these embodiments,the structure can include a spacer formed using a method describedherein.

In accordance with yet additional examples of the disclosure, a systemconfigured to perform a method and/or form a device structure asdescribed herein is provided.

These and other embodiments will become readily apparent to thoseskilled in the art from the following detailed description of certainembodiments having reference to the attached figures; the invention notbeing limited to any particular embodiment(s) disclosed.

BRIEF DESCRIPTION OF THE DRAWING FIGURES

A more complete understanding of exemplary embodiments of the presentdisclosure can be derived by referring to the detailed description andclaims when considered in connection with the following illustrativefigures.

FIG. 1 illustrates a relationship between wet etch rates and dielectricconstants of silicon oxycarbide layers.

FIG. 2 illustrates film formation using a continuous plasma power.

FIG. 3 illustrates film formation using a pulsed plasma power.

FIG. 4 illustrates a method in accordance with further examples of thedisclosure.

FIGS. 5 and 6 illustrate a timing sequence in accordance with examplesof the disclosure.

FIG. 7 illustrates a relationship between wet etch rates and dielectricconstants of silicon oxycarbide layers formed in accordance withexamples of the disclosure.

FIG. 8 illustrates a structure including a spacer formed in accordancewith examples of the disclosure.

FIG. 9 illustrates a system in accordance with at least one embodimentof the disclosure.

It will be appreciated that elements in the figures are illustrated forsimplicity and clarity and have not necessarily been drawn to scale. Forexample, the dimensions of some of the elements in the figures may beexaggerated relative to other elements to help improve understanding ofillustrated embodiments of the present disclosure.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS

Although certain embodiments and examples are disclosed below, it willbe understood by those in the art that the invention extends beyond thespecifically disclosed embodiments and/or uses of the invention andobvious modifications and equivalents thereof. Thus, it is intended thatthe scope of the invention disclosed should not be limited by theparticular disclosed embodiments described below.

The present disclosure generally relates to methods of forming a siliconoxycarbide layer on a surface of a substrate, to structures includingthe oxycarbide layer formed using the methods, and to systems forperforming the methods. As described in more detail below, exemplarymethods can be used to form structures suitable for forming electronicdevices. For example, exemplary methods can be used to form patternedstructures on a surface of a substrate. The patterned structures can beused as an etch mask or as patterned features for formation of a nextset of patterned structures. As further set forth in more detail below,exemplary methods and systems can mitigate damage to an underlayer thatmight otherwise occur during depositing of a material layer, whilemaintaining desired properties (e.g., density, etch rate, etchselectivity with regard to an underlayer material, and the like) of thedeposited material.

In this disclosure, gas may include material that is a gas at normaltemperature and pressure, a vaporized solid and/or a vaporized liquid,and may be constituted by a single gas or a mixture of gases, dependingon the context. A gas other than the process gas, e.g., a gas introducedwithout passing through a gas distribution assembly, such as ashowerhead, other gas distribution device, or the like, may be used for,e.g., sealing the reaction space, and may include a seal gas, such as arare or other inert gas. The term inert gas refers to a gas that doesnot take part in a chemical reaction to an appreciable extent and/or agas that can excite a precursor when plasma power is applied. When usedto excite a precursor, an inter gas can be a reactant. In some cases,the terms precursor and reactant can be used interchangeably.

As used herein, the term substrate can refer to any underlying materialor materials that may be used to form, or upon which, a device, acircuit, or a film may be formed. A substrate can include a bulkmaterial, such as silicon (e.g., single-crystal silicon), other Group IVmaterials, such as germanium, or compound semiconductor materials, suchas GaAs, and can include one or more layers overlying or underlying thebulk material. Further, the substrate can include various features, suchas recesses, lines, and the like formed within or on at least a portionof a layer of the substrate. By way of particular examples, a substratecan include bulk semiconductor material and/or a layer to be etched andpatterned (e.g., photoresist) features formed thereon.

In some embodiments, film refers to a layer extending in a directionperpendicular to a thickness direction to cover an entire target orconcerned surface, or simply a layer covering a target or concernedsurface. In some embodiments, layer refers to a structure having acertain thickness formed on a surface or a synonym of film or a non-filmstructure. A layer can be continuous or noncontinuous. A film or layermay be constituted by a discrete single film or layer having certaincharacteristics or multiple films or layers, and a boundary betweenadjacent films or layers may or may not be clear and may or may not beestablished based on physical, chemical, and/or any othercharacteristics, formation processes or sequences, and/or functions orpurposes of the adjacent films or layers.

In this disclosure, continuously can refer to one or more of withoutbreaking a vacuum, without interruption as a timeline, without anymaterial intervening step, without changing treatment conditions,immediately thereafter, as a next step, or without an interveningdiscrete physical or chemical structure between two structures otherthan the two structures in some embodiments. For example, a reactant canbe supplied continuously during two or more steps and/or depositioncycles of a method.

The term cyclic deposition process or cyclical deposition process orcyclic deposition cycle can refer to the sequential introduction ofprecursors (and/or reactants) into a reaction chamber to deposit a layerover a substrate and includes processing techniques such as atomic layerdeposition (ALD), cyclical chemical vapor deposition (cyclical CVD), andhybrid cyclical deposition processes that include an ALD component and acyclical CVD component. As described below, such processes can include aplasma step and be referred to as plasma-enhanced processes.

As used herein, the term purge may refer to a procedure in which aninert or substantially inert gas is provided to a reactor chamber inbetween two pulses of gases. For example, a purge may be providedbetween precursor pulses or between a precursor pulse and a plasmapulse. It shall be understood that a purge can be effected either intime or in space, or both. For example, in the case of temporal purges,a purge step can be used, e.g., in the temporal sequence of providing afirst precursor to a reactor chamber, providing a purge gas to thereactor chamber, and providing a plasma power, wherein the substrate onwhich a layer is deposited does not move. For example, in the case ofspatial purges, a purge step can take the following form: moving asubstrate from a first location to which a first precursor is supplied,through a purge gas curtain, to a second location to which a reactant issupplied.

Silicon oxycarbide (SiOC) can refer to material that includes silicon,oxygen, and carbon. As used herein, unless stated otherwise, SiOC is notintended to limit, restrict, or define the bonding or chemical state,for example, the oxidation state of any of Si, C, O, and/or any otherelement in the film. In some embodiments, SiOC may comprise one or moreelements in addition to Si, C, and O, such as H or N. In someembodiments, the SiOC may comprise Si—C bonds and/or Si—O bonds. In someembodiments, the SiOC may comprise Si—H bonds in addition to Si—C and/orSi—O bonds. In some embodiments, the SiOC may comprise from greater than0% to about 60% carbon on an atomic basis. In some embodiments, the SiOCmay comprise from about 0.1% to about 40%, from about 0.5% to about 30%,from about 1% to about 30%, or from about 5% to about 20% carbon on anatomic basis. In some embodiments, the SiOC may comprise from greaterthan 0% to about 70% oxygen on an atomic basis. In some embodiments, theSiOC may comprise from about 10% to about 70%, from about 15% to about50%, or from about 20% to about 40% oxygen on an atomic basis. In someembodiments, the SiOC may comprise greater than 0% to about 50% siliconon an atomic basis. In some embodiments, the SiOC may comprise fromabout 10% to about 50%, from about 15% to about 40%, or from about 20%to about 35% silicon on an atomic basis. In some embodiments, the SiOCmay comprise from about 0.1% to about 40%, from about 0.5% to about 30%,from about 1% to about 30%, or from about 5% to about 20% hydrogen on anatomic basis. In some embodiments, the SiOC may not comprise nitrogen.In some embodiments, the SiOC includes at least one Si—C bond and/or atleast one Si—O bond from a precursor, discussed in more detail below.

As used herein, the term overlap can mean coinciding with respect totime and within a reaction chamber. For example, with regard to gaspulse periods, such as precursor pulse periods and reactant periods, twoor more gas periods can overlap when gases from the respective pulseperiods are within the reaction chamber or provided to the reactionchamber for a period of time. Similarly, a plasma power period canoverlap with a gas (e.g., reactant gas) period (which can be continuousthrough one or more cycles, described below).

Further, in this disclosure, any two numbers of a variable canconstitute a workable range of the variable, and any ranges indicatedmay include or exclude the endpoints. Additionally, any values ofvariables indicated (regardless of whether they are indicated with aboutor not) may refer to precise values or approximate values and includeequivalents, and may refer to average, median, representative, majority,or the like in some embodiments. Further, in this disclosure, the termsinclude, including, constituted by and having can refer independently totypically or broadly comprising, consisting essentially of, orconsisting of in some embodiments. In this disclosure, any definedmeanings do not necessarily exclude ordinary and customary meanings insome embodiments.

Turning now to the figures, FIG. 1 illustrates a typical relationshipbetween dielectric constants (k value) and wet etch rate (WER) fortypical silicon oxycarbide layers. As illustrated, the dielectricconstants generally decrease as the wet etch rates of the siliconoxycarbide layer increase. For many applications, such as spacerformation applications, it may be desirable to use silicon oxycarbidelayers with both low wet etch rates and low dielectric constants.

Typical silicon oxycarbide layer deposition techniques use a continuousplasma power during a deposition cycle. FIG. 2 illustrates a structure200 and typical silicon oxycarbide layer 204 formed overlying asubstrate 202 using a continuous plasma power pulse 208. In theillustrated example, ions 206 can be relatively energetic with arelatively high plasma potential. The relatively energetic ions with therelatively high plasma potential can cause undesired damage to substrate202. Further, the relatively energetic ions with the relatively highplasma potential can result in silicon oxycarbide layer 204 with anundesirably high dielectric constant, which may result from therelatively low porosity of layer 204.

In contrast, FIG. 3 illustrates a silicon oxycarbide layer depositedusing pulsed plasma power during a deposition cycle. In FIG. 3 ,structure 300 includes a substrate 302 and a silicon oxycarbide layer304 formed overlying substrate 302. Silicon oxycarbide layer 304 can beformed using a similar plasma density as the plasma density used to formsilicon oxycarbide layer 204; however, because the plasma power ispulsed, the plasma potential is reduced, and therefore, ion 306 can havea lower energy level and/or plasma potential, compared to ions 206. Thisallows formation of silicon oxycarbide layers with desired qualitiessuch as low wet etch rates and low dielectric constants, which mayresult from the relatively higher porosity of layer 304, compared tolayer 204.

FIG. 4 illustrates a method 400 of forming a silicon oxycarbide layer inaccordance with examples of the disclosure. Method 400 can be used toform silicon oxycarbide layers with relatively low wet etch rates andrelatively low dielectric constants. Method 400 is suitable for formingpatterned structures on a surface of a substrate, which can be used in,e.g., a multiple patterning process. As illustrated, method 400 includesthe steps of providing a substrate within a reaction chamber (step 402),providing an oxygen-free reactant to the reaction chamber (step 404),providing a silicon precursor to the reaction chamber (step 406), andproviding pulsed plasma power (step 408). Method 400 can also include anoptional step of forming a spacer (step 410).

During step 402, a substrate (e.g., comprising a surface comprisingpatterned features) is provided within a reaction chamber of a reactor.The substrate can be or include any substrate described herein. Areaction chamber used during step 402 can be or include a reactionchamber of a chemical vapor deposition reactor system configured toperform a cyclical deposition process, and particularly, aplasma-enhanced cyclical deposition process. The reaction chamber can bea standalone reaction chamber or part of a cluster tool or module.

Step 402 can include heating the substrate to a desired depositiontemperature within the reaction chamber. In some embodiments of thedisclosure, step 402 includes heating the substrate to a temperature ofless than 600° C. or less than 500° C. For example, in some embodimentsof the disclosure, heating the substrate to a deposition temperature maycomprise heating the substrate to a temperature is between about 150° C.and about 300° C. or between about 100° C. and about 550° C. In additionto controlling the temperature of the substrate, a pressure within thereaction chamber may also be regulated. For example, in some embodimentsof the disclosure, the pressure within the reaction chamber during step402 may be less than 760 Torr or be between about 300 and about 1000 orbetween about 200 and about 3000 Pa. These temperatures and pressuresare also suitable for steps 404-408.

During step 404, an oxygen-free reactant is provided to the reactionchamber. Exemplary oxygen-free reactants include, for example, one ormore of argon (Ar) and hydrogen (H₂). In these cases, the oxygen-freereactant can include about 98.9 to about 99.9 or about 100 to about 90volumetric percent argon (Ar) and/or about 0.1 to about 1.1 or about 0to about 10 volumetric percent hydrogen (H₂). In accordance withspecific examples of the disclosure, the oxygen-free reactant is orincludes a mixture comprising argon (Ar) and hydrogen (H₂). A flowrateof the oxygen-free reactant to the reaction chamber can be controlledand be between about 2000 and about 4000 sccm or between about 100 andabout 6000 sccm.

During step 406, a silicon precursor is provided to the reaction chamberfor a silicon precursor pulse period. As used herein, pulse period orperiod means a time in which a gas (e.g., precursor, reactant, inertgas, and/or carrier gas) is flowed to a reaction chamber and/or a periodin which power is applied (e.g., power to produce a plasma). In somecases a period can be continuous through one or more deposition cycles.In some cases, a continuous period can include continuously providing agas to the reaction chamber. A height and/or width of illustrated pulseperiods (illustrated in FIG. 5 ) is not necessarily indicative of aparticular amount or duration of a pulse.

Exemplary silicon precursors suitable for step 406 include at least oneoxygen atom per molecule. Exemplary silicon precursors can berepresented by the formula: (R^(i))_(4-x) Si(OR^(i))_(x), where x can bebetween 1 and 3, (R^(i)—O—R^(ii))_(4-x) Si(O—R^(i))_(x), where x can bebetween 1 and 3 and (R^(i) _(3-x) Si(O—R^(i))_(x))—R^(ii)-(R^(i) _(3-x)Si(O—R^(i))_(x)), where x can be between 1 and 3. Wherein R′ is anindependently selected alkyl group (e.g., a C1-C3 alkyl group) andR^(ii) is an independently selected hydrocarbon (e.g., a C1-C4hydrocarbon). In accordance with further examples, exemplary siliconprecursor molecules can include one or more Si—O bonds. Additionally oralternatively, the molecules can include one or more Si—C bonds. In somecases, at least one Si—O and/or Si—C bond from the precursor remains inthe silicon oxycarbide layer that is formed using the precursor. By wayof particular examples, the silicon precursor can be or include one ormore of 1,2-bis(triethoxysilyl)ethane (BTESE),1,2-bis(methyldiethoxysilyl)ethane (BMDESE), dimethoxymethylvinylsilane(DMOMVS), and (3-methoxypropyl)trimethoxysilane (MPTMS).

A duration of the silicon precursor pulse period can be between about0.1 and about 1 seconds or between about 0.1 and about 2.0 seconds. Aflowrate of the silicon precursor (e.g., with a carrier gas) can bebetween about 2000 and about 4000 sccm or between about 100 and about6000 sccm. A mixture of the silicon precursor and the carrier gas caninclude about 0.1 to about 40_volumetric percent of the siliconprecursor.

During step 408, a pulsed plasma power is provided to an electrode(e.g., within the reactor) for a plasma power period to form a plasmawithin the reactor. During this step, the silicon precursor within thereaction chamber can polymerize and form the silicon oxycarbide layer.

A plasma power used during step 408 can be between about 100 and about500 or between about 50 and about 1500 W. A duration of the plasma powerperiod can be between 0.01 and 5.0 seconds. A plasma pulse period, i.e.,a duration of each pulse of plasma power during the plasma power periodcan be between about 0.01 and 0.2 msec. A plasma power on-time dutycycle can be greater than 0 and less than 75% or between about 10 andabout 50%. A frequency of the pulsed plasma power can be between about10,000 and 100,000 Hz or about 5,000 and 200,000 Hz.

As illustrated, method 400 can include step 410 of forming a spacer.Step 410 can include etching a portion of the silicon oxycarbide layerformed using steps 402-408 to forms spacers about a feature on thesubstrate surface. An exemplary spacer is illustrated below in FIG. 8 .

FIGS. 5 and 6 illustrate an exemplary timing sequence 500 suitable formethod 400. In the illustrated example, a reactant is provided to thereaction chamber for a reactant period 502, a silicon precursor isprovided to the reaction chamber for a silicon precursor pulse period504, and a plasma power is applied to form a plasma during plasma powerperiod 508. Sequence 500 can include one or more deposition cycles 508.Each deposition cycle 508 includes a silicon precursor pulse period 504and a plasma power period 506, while reactant period 502 can becontinuous through one or more deposition cycles 508.

Sequence 500 can also include a carrier gas period 510. During carriergas period 510, a carrier gas (e.g., used to facilitate providing asilicon precursor), such as one or more of argon, helium, alone or inany combination, is provided to the reaction chamber. A flowrate of thecarrier gas can be between about 500 and about 5000 sccm. Carrier gasperiod 510 can overlap with reactant period 502.

In the illustrated example, silicon precursor pulse period 504 ceasesprior to plasma power period 506. Reactant period 502 and a carrier gasperiod 510 can be continuous through one or more deposition cycles 508.In some cases, during a continuous period, a flowrate of the reactantand/or carrier gas can change—e.g., such that a total (e.g., volumetric)flowrate of gas to the reaction chamber remains about constant during anoverlap of periods 502, 504, and 510.

FIG. 6 illustrates plasma power period 506 in greater detail. Asillustrated, plasma power period 506 includes a plurality of on-offcycles 602, where each on-off cycle 602 can have an on-time 604 and anoff-time 606, where a percent duty can be on-time/(on-time + off-time).Exemplary durations of plasma power period 506, on-off cycles (plasmapulse periods) 602, and percent on-time or percent duty 604 are providedabove.

As noted above, an advantage of methods described herein is that asilicon oxycarbide layer with desired properties can be formed, whilealso mitigating any undesired damage to an underlying layer orsubstrate. FIG. 7 illustrates dielectric constants (k value) and wetetch rates (WER) for silicon oxycarbide layer formed according to amethod described herein (darker dots). As shown, silicon oxycarbidelayers with a dielectric constant of the silicon oxycarbide layer ofless than 4.5, less than 4.25, or less than 4 or between about 3.5 andabout 4.25 and/or with a wet etch rate of the silicon oxycarbide layerin 0.5% dilute hydrofluoric acid of less than 1 nm/minute, less than 0.8nm/minute, less than 0.6 nm/minute, or between 0.4 nm/minute and 0.9nm/minute were formed using a method described herein.

FIG. 8 illustrates another structure formed in accordance with examplesof the disclosure. Structure 800 includes a substrate 802, a feature804, and spacers 806 and 808. Substrate 802 can be or include anysubstrate described herein. Feature 804 can include a photoresistfeature, or a metallic, semiconductive, or dielectric patterned feature.Spacers 806 and 808 can be formed by depositing a silicon oxycarbidelayer—e.g., according to method 400 and then removing a portion of thelayer.

Turning now to FIG. 9 , a reactor system 900 in accordance withexemplary embodiments of the disclosure is illustrated. Reactor system900 can be used to perform one or more steps or substeps as describedherein and/or to form one or more structures or portions thereof asdescribed herein.

Reactor system 900 includes a pair of electrically conductive flat-plateelectrodes 914, 918 in parallel and facing each other in an interior 901(reaction zone or reaction chamber) of a reactor 902. Althoughillustrated with one reactor 902, system 900 can include two or morereactors or reaction chambers. A plasma can be excited within reactor902 by applying, for example, RF power from plasma power source(s) 908to one electrode (e.g., electrode 918) and electrically grounding theother electrode (e.g., electrode 914). A temperature regulator 903 canbe provided in a lower stage 914 (the lower electrode), and atemperature of a substrate 922 placed thereon can be kept at a desiredtemperature, such as the temperatures noted above. Electrode 918 canserve as a gas distribution device, such as a shower plate orshowerhead. Precursor gases, reactant gases, a carrier or inert gas, andthe like can be introduced into reaction space 901 using one or more gaslines (e.g., reactant gas line 904 coupled to a reactant source 930(e.g., an oxygen-free reactant as described herein)) and precursor gasline 906 coupled to a silicon precursor source 931 and an inert gassource 934. For example, an inert gas and a reactant (e.g., as describedabove) can be introduced into reaction space 901 using line 904 and/or aprecursor and a carrier gas (e.g., as described above) can be introducedinto reaction space 901 using line 906. Although illustrated with twoinlet gas lines 904, 906, reactor system 900 can include any suitablenumber of gas lines. A flow control system including flow controllers932, 933, 935 can be used to control the flow of one or more reactants,precursors, and inert gases into reaction space 901.

In reactor 902, a circular duct 920 with an exhaust line 921 can beprovided, through which gas in the interior 901 of reactor 902 can beexhausted to an exhaust source 910. Additionally, a transfer chamber 923can be provided with a seal gas line 929 to introduce seal gas into theinterior 901 of reactor 902 via the interior (transfer zone) of transferchamber 923, wherein a separation plate 925 for separating the reactionzone 901 and the transfer chamber 923 can be provided (a gate valvethrough which a substrate is transferred into or from transfer chamber923 is omitted from this figure). Transfer chamber 923 can also beprovided with an exhaust line 927 coupled to an exhaust source 910. Insome embodiments, continuous flow of a carrier gas to reaction chamber901 can be accomplished using a flow-pass system (FPS).

Reactor system 900 can include one or more controller(s) 912 programmedor otherwise configured to cause one or more method steps as describedherein to be conducted. Controller(s) 912 are coupled with the variouspower sources, heating systems, pumps, robotics and gas flowcontrollers, or valves of the reactor, as will be appreciated by theskilled artisan. By way of example, controller 912 can be configured tocontrol gas flow of a precursor, a reactant, and an inert gas into atleast one of the one or more reaction chambers to form a layer on asurface of a substrate. Controller 912 can be further configured toprovide power—e.g., within reaction chamber 901. Controller 912 can besimilarly configured to perform additional steps as described herein. Byway of examples, controller 912 can be configured to control gas flow ofa precursor, an inert gas, and a reactant into at least one of the oneor more reaction chambers to form a silicon oxycarbide layer overlying asubstrate.

Controller 912 can include electronic circuitry and software toselectively operate valves, manifolds, heaters, pumps and othercomponents included in system 900. Such circuitry and components operateto introduce precursors, reactants, and purge gases from the respectivesources. Controller 912 can control timing of gas pulse sequences,temperature of the substrate and/or reaction chamber, pressure withinthe reaction chamber, and various other operations to provide properoperation of the system 900.

Controller 912 can include control software to electrically orpneumatically control valves to control flow of precursors, reactants,and/or purge gases into and out of the reaction chamber 901 and reactor902. Controller 912 can include modules, such as a software or hardwarecomponent, e.g., a FPGA or ASIC, which performs certain tasks. A modulecan advantageously be configured to reside on the addressable storagemedium of the control system and be configured to execute one or moreprocesses.

By way of particular examples, controller 912 is configured to controlgas flow of a silicon precursor for a silicon precursor pulse, (e.g.,continuous) flow of a an oxygen-free reactant during one or more cycles,and a power plasma pulse (e.g., a power level, duration and/or dutycycle of the plasma pulse).

In some embodiments, a dual chamber reactor (two sections orcompartments for processing substrates disposed close to each other) canbe used, wherein a reactant gas and a noble gas can be supplied througha shared line, whereas a precursor gas is supplied through unsharedlines.

During operation of system 900, substrates, such as semiconductorwafers, are transferred from, e.g., a substrate handling area 923 to thereaction zone 901. Once substrate(s) are transferred to reaction zone901, one or more gases, such as precursors, reactants, carrier gases,and/or purge gases, are introduced into reaction chamber 901.

The example embodiments of the disclosure described above do not limitthe scope of the invention, since these embodiments are merely examplesof the embodiments of the invention. Any equivalent embodiments areintended to be within the scope of this invention. Indeed, variousmodifications of the disclosure, in addition to the embodiments shownand described herein, such as alternative useful combinations of theelements described, may become apparent to those skilled in the art fromthe description. Such modifications and embodiments are also intended tofall within the scope of the appended claims.

1. A method of forming a silicon oxycarbide layer on a surface of a substrate, the method comprising the steps of: providing a substrate within a reaction chamber of a reactor; providing an oxygen-free reactant to the reaction chamber; and performing one or more deposition cycles, wherein each deposition cycle comprises: providing a silicon precursor to the reaction chamber for a silicon precursor pulse period, the silicon precursor comprising at least one oxygen atom per molecule; and providing pulsed plasma power to an electrode for a plasma power period to form a plasma within the reactor.
 2. The method of claim 1, wherein the oxygen-free reactant comprises one or more of argon (Ar) and hydrogen (H₂).
 3. The method of claim 1, wherein the oxygen-free reactant comprises about 98.9 to about 99.9 or about 100 to about 90 volumetric percent argon (Ar).
 4. The method of claim 1, wherein the oxygen-free reactant comprises about 0.1 to about 1.1 or about 0 to about 10 volumetric percent hydrogen (H₂).
 5. The method of claim 1, wherein the oxygen-free reactant comprises a mixture comprising argon (Ar) and hydrogen (H₂).
 6. The method of claim 1, wherein a duration of the plasma power period is between 0.01 and 5.0 seconds.
 7. The method of claim 1, wherein a plasma power on-time duty cycle is greater than 0 and less than 75% or between about 10 and about 50%.
 8. The method of claim 1, wherein the molecule comprises one or more Si—O bonds.
 9. The method of claim 1, wherein the molecule comprises one or more Si—C bonds.
 10. The method of claim 1, wherein the silicon precursor is represented by the formula: (R^(i))_(4-X) Si(O—R^(i))_(x), where x can be between 1 and 3, (R^(i)—O—R^(ii))_(4-x) Si(O—R^(i))_(x), where x can be between 1 and 3 and (R^(i) _(3-x) Si(O—R^(i))_(x))—R^(ii)-(R^(i) _(3-x) Si(O—R^(i))_(x)), where x can be between 1 and
 3. Wherein R^(i) is an independently selected alkyl group and R^(ii) is an independently selected hydrocarbon.
 11. The method of claim 1, wherein the silicon precursor comprises one or more of 1,2-bis(triethoxysilyl)ethane (BTESE), ), dimethoxymethylvinylsilane (DMOMVS), 1,2-bis(methyldiethoxysilyl)ethane (BMDESE), and (3-methoxypropyl)trimethoxysilane (MPTMS).
 12. The method of claim 1, wherein the silicon oxycarbide layer forms a spacer.
 13. The method of claim 1, wherein a dielectric constant of the silicon oxycarbide layer is less than 4.5.
 14. The method of claim 1, wherein a wet etch rate of the silicon oxycarbide layer in 0.5% dilute hydrofluoric acid is less than 1 nm/minute.
 15. The method of claim 1, wherein the reactant is continuously provided to the reaction chamber during a deposition cycle of the one or more deposition cycles.
 16. The method of claim 1, wherein the reactant is continuously provided to the reaction chamber during two or more deposition cycles.
 17. The method of claim 1, wherein the silicon precursor pulse period ceases prior to the plasma power period.
 18. The method of claim 1, wherein a duration of the silicon precursor pulse period is between about 0.1 and about 1 seconds or between about 0.1 and about 2.0 seconds.
 19. The method of claim 1, wherein a temperature of the substrate is between about 150 and about 300 or between about 100 and about 550° C.
 20. The method of claim 1, wherein a pressure within the reaction chamber during the deposition cycle is between about 300 and about 1000 or between about 200 and about 3000 Pa.
 21. A structure formed according to the method of claim
 1. 